Marine Iguana
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40 free Marine Iguana trivia questions with answers — trivia quiz, new questions added Oct 2026.
The marine iguana is the only lizard in the world that makes its living in the ocean. It is found on one remote group of volcanic islands and nowhere else, and early visitors thought it one of the ugliest animals they had ever seen. This quiz turns the best marine iguana fun facts into questions. They cover how the animal feeds underwater, how it copes with salt and cold, how rivals fight and mothers nest, what hunts it, how it survives the lean years, and the odd places it has turned up in science and on screen. It suits wildlife fans, students, teachers and anyone planning a trip to the Galápagos. Every answer comes with a short explanation, so you will finish knowing far more about these lizards than when you started.
30 of 40 questions with answers and explanations. Play the quiz
Q 01How do marine iguanas get rid of the extra salt they swallow while feeding in the sea?
Sneezing it out
Sneezing it out clears the salt that glands at the nostrils filter from the blood. The spray often dries on the head as a crusty white wig.
Q 02What can adult marine iguanas do to their own bodies to survive years when food runs short?
Shrink in length
Shrink in length is the trick, by as much as a fifth, and researchers suspect the bones themselves shorten. The iguanas grow back once the seaweed returns.
Q 03Which movie monster gives its name to a marine iguana subspecies from San Cristóbal Island?
Godzilla
Godzilla was a fitting choice: the designer of the 1998 Hollywood film modelled its monster on iguanas instead of the upright Japanese original.
Q 04Which naturalist threw a marine iguana into the sea again and again in 1835, only to see it swim back?
Charles Darwin
Charles Darwin found the lizard came straight back to the spot where he stood every time. He guessed that instinct told it the shore was safer than the sea.
Q 05Española's marine iguanas flush with bright colour when breeding, earning a nickname from which holiday?
Christmas
Christmas iguanas flush red and green, and the name fits twice over: the colours are brightest in the breeding season, which begins in December.
Q 06Which BBC series made a viral sensation of marine iguana hatchlings fleeing from snakes in 2016?
Planet Earth II
Planet Earth II showed a group of racer snakes hunting the hatchlings in its Islands episode, and the clip spread across the internet that November.
Q 07What did a sailor find in 1835 on hauling up a marine iguana he had sunk with a weight for an hour?
It was quite active
It was quite active, an early clue to how long these lizards can hold their breath: a feeding dive may last more than half an hour.
Q 08Which body part does most of the work of driving a swimming marine iguana through the water?
Its tail
Its tail is flattened from side to side and sweeps the animal along like a crocodile, while the legs mostly trail and the feet are barely webbed.
Q 09Which climate event kills off seaweed and can starve up to 90% of an island's marine iguanas?
El Niño
El Niño cuts off the cold water that the seaweed needs, and the biggest iguanas suffer most because they need the most food.
Q 10When do most marine iguanas, which never dive, graze on the seaweed growing on the shoreline rocks?
At low tide
At low tide the rocks lie bare, so the smaller iguanas dash down, snatch a few bites and run back to higher ground before the next wave arrives.
Q 11Which country governs the Galápagos and fully protects the marine iguana under its laws?
Ecuador
Ecuador keeps almost all of the iguana's range on shore inside a national park, and all of its range at sea inside a marine reserve.
Q 12In which ocean, cold here despite the equator, do all wild marine iguanas find their food?
Pacific
Pacific water around the islands is only 11 to 23 °C at the surface, so every feeding trip chills the iguana and has to be kept short.
Q 13Which far bigger mammal shares the shore with marine iguanas, which sometimes crawl right over it?
Sea lions
Sea lions and iguanas mostly ignore each other, and neither animal seems to gain anything from living side by side.
Q 21Which bird is the main native predator of marine iguanas, able to take even weakened full-grown ones?
Galápagos hawk
The Galápagos hawk is itself rare, with only a few hundred birds alive, so native hunters trouble the iguanas far less than introduced ones.
Q 22What happens to a marine iguana's heartbeat when it plunges into the cold sea to feed?
It slows sharply
It slows sharply, to about 30 beats a minute against roughly 100 on sun-baked rock, so the blood circulates less and less warmth is lost.
Q 23Which gloomy nickname for marine iguanas was recorded in a famous diary of an 1835 visit?
Imps of darkness
Q 14Which introduced predator can kill fully grown marine iguanas, not only their eggs and young?
Feral dogs
Feral dogs are hard to remove safely, because they also hold cat numbers down, and cats prey on the small iguanas.
Q 15How do rival marine iguanas usually settle a fight over a patch of breeding territory?
Butting heads
Butting heads is the rule: bony plates on the skull lock together and each lizard shoves, sometimes for hours, until the loser backs away.
Q 16Where does a marine iguana mother leave her eggs to hatch on their own a few months later?
In a sandy burrow
In a sandy burrow up to 80 cm deep, which she digs herself in sand or volcanic ash; where good sites are scarce she guards it against other mothers.
Q 17Why do marine iguanas often spend the night pressed together in groups of up to fifty?
To conserve heat
To conserve heat, the iguanas huddle because a reptile makes no warmth of its own and must hold on to what the day's sun gave it.
Q 18How do marine iguanas usually react when a person walks right up to them on the shore?
They stay put
They stay put, having evolved with few land predators to fear; even iguanas that have been caught before are only slightly more wary the next time.
Q 19How are the marine iguana's ancestors thought to have reached the Galápagos from the mainland?
Drifting on debris
Drifting on debris such as logs is the leading idea, because the volcanic islands were never joined to any continent.
Q 20Why do marine iguanas at midday face the sun and lift their bodies high above the hot rock?
To cool off
To cool off, the iguana points itself at the sun so that little of it is lit and lets air flow underneath; it pants as well.
Imps of darkness suited lizards as black as the lava they crawl over, and the dark colour helps them soak up sunshine quickly after a cold swim.
Q 24What do newly hatched marine iguanas feed on to pick up the gut bacteria that digest seaweed?
Their elders' droppings
Their elders' droppings carry the microbes that break seaweed down, and a hatchling needs them before it can digest its own diet.
Q 25Which colour of seaweed can marine iguanas barely digest, starving when no other kind is left?
Brown
Brown seaweed can take over the rocks when the red and green kinds die back in hot years, and iguanas left with nothing else go hungry.
Q 26Which technology has helped researchers and online volunteers count marine iguanas on remote Galápagos shores?
Aerial drones
Aerial drones photograph the colonies for the Iguanas from Above project, and citizen scientists help count the animals in what is meant to be the first full survey of the species.
Q 27What kind of disaster in 2001 cut Santa Fé Island's marine iguana population by almost two-thirds?
An oil spill
An oil spill from the ship Jessica did the damage even at low doses, probably by killing the gut bacteria that iguanas need to digest their food.
Q 28What matters most to a marine iguana choosing which territory holder she will mate with?
His sheer size
His sheer size counts most, with frequent head-bobbing and a well-placed plot also helping, while the area of the plot makes no difference.
Q 29How do small marine iguanas manage to mate unnoticed inside a bigger rival's guarded territory?
They resemble females
They resemble females in build and colour, so the owner overlooks them; they must be quick, because he chases them out as soon as he notices.
Q 30What does Amblyrhynchus, the Greek-derived genus name of the marine iguana, mean in English?
Blunt snout
Blunt snout describes the flat face that lets the iguana press close to the rock and scrape off short seaweed with its sharp teeth.